1. Field of the Invention
This invention relates to a device for releasing the flow of water in a water faucet in which switch means are provided which are actuated by an operating member projecting from the discharge opening, in which a hollow cylindrical body having an inlet and an outlet opening is connectible to the discharge head of the water faucet, and in which the switching means include a valve member fitted in a valve seat to face the discharge opening and being adapted to be lifted from the valve seat by the action of the operating member.
2. Description of the Prior Art
A device of the foregoing type is known from German patent specification DE-PS No. 714 423. In this prior device, the operating member is fixedly joined to the valve member and is mounted on the casing so as to be adjustable along the longitudinal axis of the casing. To start the water running, the operating member must be raised, thereby causing the valve member to be lifted, so that the discharge opening is exposed which continues to extend inside the hollow actuating member. The operating member is provided with peripheral handles for being taken hold of from the outside of the discharge opening.
This known prior device is suitable merely for starting and stopping the flow of water. It is not suitable, however, for a water faucet in which the flow of water is to be controlled solely by moving the hands to be washed under the discharge opening or spout. The necessity of constantly lifting the operating member is prohibitive of any rubbing of the hands requisite for a proper washing procedure.
In order to reduce the volume of water used during the washing of hands, equipment is required which can be operated as the hands are moved under the spout but which will still permit unlimited rubbing of the hands during the washing procedure.
To this end, various switching devices are available to monitor the movements of the hands into and out of the area below the water faucet spout.
German patent specification DE-OS Nos. 27 21 154, 30 25 603 and 30 35 935 disclose the use of optoelectric switching means installed in the discharge member of the water faucet.
German patent specification DE-OS No. 27 55 665 discloses the use of proximity switches as switching means, and German patent specification Nos. 27 21 217, 27 21 225 and 27 21 254 describe the use of ultrasonic motion detectors as switching means for devices of this type.
Common to all of these prior art devices is that the structural requirements for the switching device are considerable, and that they cannot readily be installed in existing water faucets.